In a single liquid processing unit (a liquid processing apparatus) in which a liquid processing is performed on a semiconductor wafer (hereinafter, referred to as a “wafer”) serving as a substrate by supplying various processing liquids, an alkaline or acidic chemical liquid is supplied to a wafer surface that is rotating to remove dusts or natural oxides from the wafer surface. The chemical liquid remaining on the wafer surface is removed by a rinse liquid. When the supply of the rinse liquid is stopped while rotating the wafer, the remaining rinse liquid is scattered, so that the wafer is dried.
In the liquid processing unit, a holding unit that rotatably holds the wafer may be provided with a mechanism configured to adjust a flow of a processing liquid discharged from the wafer. For example, Japanese Patent Laid-Open No. 2008-34656 discloses a liquid processing apparatus in which a guide member (a guide unit) configured to guide a processing liquid is provided at substantially the same height as the wafer so as to surround the wafer held in a floating state from a top surface of a rotary plate (a holding unit) by a holding member. The guide member is interposed between an eaves portion provided at an end of the rotary plate and an outer wall (a rotary cup), and the rotary plate (see, e.g., paragraphs 0013, 0019 to 0021, and FIG. 4).
According to the liquid processing apparatus, the processing liquid, or mist generated during the flow is guided to a front or rear surface of the guide member, introduced into a gap between the outer wall and the rotary plate, and then discharged to a lower side of the wafer while changing the flow direction. Therefore, the wafer may be suppressed from being contaminated by backflow of the mist.
However, in the above-mentioned rotary plate, a plurality of holding members is disposed to be spaced apart from each other around the wafer so that the wafer is held by inserting an end surface of the wafer between the plurality of holding members. Therefore, when a force is applied from different positions with respect to the end surface of the wafer, the wafer may be distorted as if the wafer waves along the circumferential direction so that the height of the periphery is changed. When a liquid processing is performed in a state where the wafer is distorted, the processing liquid discharged from the wafer may collide with a body of the guide member, and hence, mist generated by the collision may contaminate the wafer. Further, the processing liquid discharged from the wafer may not be discharged towards a cup by the guide member.